U.S. patent number 4,437,986 [Application Number 06/421,613] was granted by the patent office on 1984-03-20 for separating device and cartridge therefor.
This patent grant is currently assigned to Fram Corporation. Invention is credited to Charles K. Hutchins, Richard H. Peyton, Donald I. Thornton.
United States Patent |
4,437,986 |
Hutchins , et al. |
March 20, 1984 |
**Please see images for:
( Certificate of Correction ) ** |
Separating device and cartridge therefor
Abstract
Separating device for separating the liquid components of a
liquid mixture comprising an annular coalescing medium (84) for
causing the liquid component to be removed from the mixture to
coalesce into droplets, and a conical separating medium (102)
tapering toward a liquid collecting sump (98). A heating element
(46) heats the liquid mixture when the temperature of the mixture
is below a predetermined temperature. An open, fibrous batt of
filtering material (100) circumscribes the coalescing medium (84)
to collect wax crystals which form during cold temperature
conditions. A relief valve (108) permits liquid to bypass the
separating medium (102) when the pressure differential across the
separating medium (102) exceeds a predetermined amount.
Accordingly, initial flow through the separating device is
established, permitting the heater to heat the liquid to a
temperature above that at which wax crystals form.
Inventors: |
Hutchins; Charles K. (East
Providence, RI), Thornton; Donald I. (East Providence,
RI), Peyton; Richard H. (East Providence, RI) |
Assignee: |
Fram Corporation (East
Providence, RI)
|
Family
ID: |
23671293 |
Appl.
No.: |
06/421,613 |
Filed: |
September 22, 1982 |
Current U.S.
Class: |
210/130;
210/DIG.5; 210/149; 210/184; 210/416.4; 219/205; 219/505;
392/484 |
Current CPC
Class: |
B01D
17/045 (20130101); F02M 37/36 (20190101); B01D
35/143 (20130101); B01D 17/0214 (20130101); B01D
36/003 (20130101); B01D 35/26 (20130101); F02M
37/34 (20190101); F02M 37/54 (20190101); B01D
35/147 (20130101); B01D 35/18 (20130101); F02M
37/28 (20190101); C10G 33/06 (20130101); B01D
17/10 (20130101); F02M 37/44 (20190101); F02M
37/30 (20190101); B01D 17/00 (20130101); Y10S
210/05 (20130101) |
Current International
Class: |
B01D
36/00 (20060101); C10G 33/00 (20060101); B01D
17/00 (20060101); B01D 35/14 (20060101); B01D
35/143 (20060101); B01D 35/18 (20060101); B01D
35/00 (20060101); C10G 33/06 (20060101); F02M
37/22 (20060101); B01D 027/10 () |
Field of
Search: |
;210/86,114,115,130,131,137,416.4,DIG.5,180,184 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Adee; John
Attorney, Agent or Firm: Decker; Ken C. Antonis; W. N.
Claims
We claim:
1. Separator cartridge for separating immiscible components of a
liquid mixture comprising a casing having inlet and outlet
connections adapted for communication to a liquid flow system, an
annular coalescing medium within said casing for causing the liquid
component to be separated from said mixture to agglomerate into
liquid droplets, said coalescing medium having inner and outer
surfaces, a sump defined within said casing for collecting the
liquid to be separated from the liquid mixture, means in said
casing for deflecting liquid flow through said inlet connection to
the outer surface of said coalescing medium, a separating medium
coaxial with said coalescing medium and located downstream of the
latter so that the liquid mixture flows through the coalescing
medium before reaching the separating medium, said liquid mixture
flowing from the inner surface of said coalescing medium to said
separating medium while allowing at least some of the coalesced
liquid droplets of the liquid to be removed from said mixture to
deposit in said sump, the surface of said separating medium being a
material repellant to the liquid to be removed from said mixture so
that droplets of the liquid to be removed deposit on said surface
and fall into said sump while the other liquid of said liquid
mixture passes therethrough, and pressure differential responsive
means opening to permit said liquid mixture to bypass said
separating medium when pressure differential across said separating
medium attains a predetermined level, said pressure differential
responsive means closing when the pressure differential drops below
the predetermined level.
2. Separating cartridge as claimed in claim 1, including the baffle
means between said coalescing medium and said separating medium for
turning the flow of said liquid mixture after said liquid mixture
leaves said coalescing medium.
3. Separating cartridge as claimed in claim 2 wherein said baffle
means is a sleeve receiving said separating medium;
4. Separating cartridge as claimed in claim 1, wherein said
separating medium is conical, and said pressure differential
responsive means is a relief valve mounted in the tip of said
conical separating medium and permits flow of said liquid mixture
to bypass said separating medium when the pressure differential
across said separating medium attains a predetermined level.
5. Separating cartridge as claimed in claim 4 wherein said
coalescing medium comprises an annular array of radially tapering
pleats circumscribed by a batt of randomly arrayed fibrous
filtering material which is less restrictive to liquid flow than is
the array of pleats.
6. Separating cartridge as claimed in claim 4, wherein said
coalescing medium includes a more dense array of filtering material
circumscribed by a less dense array of filtering material.
7. Separating device for separating immiscible components of a
liquid mixture in which wax crystals form when the temperature is
below a predetermined temperature, comprising a housing having
inlet and outlet fittings for connection in a liquid flow system, a
sump for collecting liquid separated from said mixture and means to
effect separation of water from said mixture, said housing having a
heating element for heating the liquid flowing through said device
to a temperature above said predetermined temperature, said heating
element being located in the flowpath in said housing between said
inlet and outlet fittings, said separating effecting means
including an annular coalescing medium within said housing, a
separating medium in said housing arranged so that said mixture
flows through said coalescing medium before reaching said
separating medium, and pressure differential responsive means
responsive to a predetermined differential pressure for permitting
said liquid mixture to bypass said separating medium after said
liquid mixture has passed through the coalescing medium and closing
when said pressure differential across said pressure differential
responsive means drops below said predetermined differential
pressure, said predetermined differential pressure being set at a
pressure level at which the wax crystals in the liquid mixture may
cause said separating medium to be restricted by said wax crystals,
said pressure differential responsive means closing when a
sufficient quantity of the liquid mixture has been bypassed around
said separating medium to permit the liquid heated by the heating
element to reach the separating medium at which time the pressure
differential across said pressure differential responsive means
drops below said predetermined differential pressure.
8. Separating device as claimed in claim 7, wherein said heating
element is located within a circumferentially extending duct in
said housing, and means for communicating said liquid mixture into
said duct for flow therethrough.
9. Separating device as claimed in claim 8, including means to
supply electrical energy to said electrically resistive
material.
10. Separating device as claimed in claim 7 wherein said housing
includes a manually operable pump for moving the liquid mixture
from said inlet fitting to said outlet fitting, a manually operable
vent at said outlet fitting to permit air to escape from said
cartridge when said pump is operated, and a manually operable drain
cock on said sump to permit operation of said pump to force the
separated liquid from said sump through said drain cock.
11. Separating device as claimed in claim 7, wherein said
coalescing medium includes a batt of randomly arrayed fibrous
filtering material circumscribing a second filtering material which
is more restrictive to liquid flow than is said batt.
12. Separating device as claimed in claim 7, wherein said heating
element is mounted in a circumferentially extending duct in said
housing, means for communicating said liquid mixture into said duct
for flow therethrough and from said duct to the inlet connection to
the cartridge, and means to supply electrical energy to said
ring.
13. Separating device as claimed in claim 12, wherein said heating
element includes a pair of positive temperature coefficient
elements mounted in said duct.
Description
This invention relates to a separating device for separating the
liquid components of a liquid mixture, and is particularly useful
for removing water and other contaminants from the fuel oil in a
diesel engine fuel supply system.
Separating devices have been proposed before. They are of the type
which include a casing having inlet and outlet connections adopted
for communication to a liquid flow system, an annular coalescing
medium within the casing for causing the liquid component to be
separated from the mixture to agglomerate into liquid droplets, the
coalescing medium having inner and outer surfaces, a sump defined
within said casing for collecting the liquid to be separated from
the liquid mixture, means within the casing for deflecting liquid
flow through the inlet connection to the outer surface of the
coalescing medium, and a separating medium within the casing for
separating the droplets coalesced by the coalescing medium from the
liquid mixture.
This type of separating device is shown, for example, in U.S. Pat.
No. 4,276,161 issued June 30, 1981 and U.S. Pat. No. 4,321,136
issued Mar. 23, 1982, both to Matsui et al. Unfortunately, one
problem inherent in the devices disclosed in the Matsui et al
patents and other devices known to prior art is the phenomenon
known as "waxing". When certain liquids, such as diesel fuel, are
cooled to a sufficiently low temperature, wax crystals are formed.
In normal diesel fuel systems, formation of some wax crystals is
not a severe problem because such systems are equipped with heaters
which heat the fuel during operation of the engine to a temperature
above that at which the wax crystals form. However, the wax
crystals in the fuel do become a problem if the fuel system is
equipped with a fuel oil filter and/or separator, because the wax
crystals are a contaminant which may plug the fuel filter and/or
separator media, thereby causing an insufficient flow of fuel to
the vehicle engine. Another problem inherent in diesel fuel
oil/water separators is that some of the coalesced water particles
may find their way to the outlet of the separator, particularly
when the water content of the fuel oil is high.
The present invention avoids the drawbacks of the prior art by
providing a relief valve which bypasses the separating medium when
the pressure differential across the separating medium exceeds a
predetermined level, and by providing a batt of loosely woven
fibrous material circumscribing the coalescing medium to collect
the wax particles before they have a chance to contaminate the
coalescing medium. Accordingly, fuel flow thrugh the water
separator is sufficient to permit heating elements to warm the fuel
to a point where waxing is no longer a problem, at which point the
fuel oil/water separator functions normally. The invention also
provides a conical separating medium which points towards the sump
which receives the water droplets. Because of the conical shape,
water particles are much more likely to gather on the separating
material and drop directly in the sump than they were in devices
known in the prior art.
The present invention is characterized by relief valve means
responsive to a predetermined pressure differential across the
separating medium to permit flow of said liquid mixture to bypass
said separating medium, said coalescing medium comprising a batt of
randomly arranged fibrous filtering material circumscribing a
second filtering material that is more restrictive to liquid flow
than is the batt. The invention is further characterized in that a
conical separating medium is provided coaxial with the coalescing
medium when the liquid mixture flowing from the inner surface of
the coalescing medium to the separating medium causes at least some
of the coalesced liquid droplets to be removed from the mixture and
to deposit in the sump, and the conical surface of the separating
medium being a material repellent to the liquid to be removed from
the mixture so that droplets of the liquid to be removed deposit on
the conical surface and fall to the sump while the other liquid of
the liquid mixture passes therethrough.
The present invention has the advantageous effects of providing a
relatively compact heater within the separator housing itself to
heat the liquid mixture as it passes therethrough, by providing a
batt of less dense filter material circumscribing the more dense
coalescing medium in order to trap wax particles on the fibers of
the batt that would otherwise plug the coalescing medium, and by
providing a relief valve that permits liquid flow to bypass the
separating medium during cold weather viscous flow conditions,
thereby permitting flow of fluid through the separator while the
heater heats the liquid mixture to a satisfactory range. Another
advantageous effect of the invention is the design of the separator
cartridge, in which a conical shaped separating medium enhances
removal of water from the fuel oil mixture and by the provision of
a baffle between the separating and coalescing mediums so that the
liquid mixture must make a 180.degree. turn in order to reach the
separating medium, thereby even further enhancing the likelihood
that water droplets coalesced by the coalescing medium will remove
themselves from the flow and fall into the sump.
Although a specific embodiment of the invention has been disclosed
herein, the scope of the invention is not limited thereto, and many
variations of the concepts disclosed herein are possible.
Accordingly, the scope of the invention is limited only by the
scope of the appending claims.
With respect to the drawings:
FIG. 1 is a longitudinal cross-sectional view of a separating
device made pursuant to the teachings of our present invention,
taken substantially along lines 1--1 of FIG. 2;
FIG. 2 is a top plan view of a separator made pursuant to the
teachings of our present invention;
FIG. 3 is a fragmentary partial cross-sectional view taken
substantially along lines 3--3 of FIG. 2;
FIG. 4 is a fragmentary cross-sectional view taken substantially
along lines 4--4 of FIG. 2;
FIG. 5 is an enlarged longitudinal cross-sectional view of the
circumscribed portion of FIG. 1; and
FIG. 6 is a view taken substantially along lines 6--6 of FIG. 5
illustrating the tip and body portions of the probe assembly.
Referring now to the drawings, a separator device for separating an
immiscible component from a fluid mixture, such as separating water
from diesel fuel oil in the fuel supply system of an automobile
equipped with a diesel engine, is indicated generally by the
numeral 10. Separating device 10 includes a housing or mount 12,
which is secured, for example, to an automotive vehicle, and a
replaceable separator cartridge generally indicated by the numeral
14 which is carried on the housing 12 and which is replaceable at
normal maintenance intervals. The housing 12 is provided with an
inlet fitting 16 and an outlet fitting 18 for connection in the
aforementioned fuel supply system of a motor vehicle. The inlet
fitting 16 communicates with an inlet passage 20 which communicates
fluid from the inlet fitting 16 into the pumping chamber 22 of a
hand operated primer pump generally indicated by the numeral 24. A
one-way check valve 36 permits fluid communication from the inlet
fitting 16 into the pumping chamber 22, but prevents communication
in the reverse direction.
The primer pump 24 includes a pumping diaphragm 26 which is
sealingly secured at its outer periphery to circumferentially
extending portion 28 of the housing 12. The diaphragm 26 separates
the pumping chamber 22 from a vented chamber 30. A reciprocally
mounted, hand operated plunger 32 is secured to the diaphragm 26
and is adapted to move the latter toward and away from the housing
12 when the plunger 32 is operated. A spring 34 yieldably urges the
plunger 32 upwardly viewing the figure. A check valve assembly 36
permits communication of liquid mixture into the pumping chamber 22
from the inlet fitting 16, but prevents communication in the
reverse direction. A second check valve 38 permits communication
from the pumping chamber 22 into a passage portion 40 downstream of
the pumping chamber 22, but prevents communication in the reverse
direction.
Passage portion 40 communicates liquid through an opening (not
shown) 42 in top portion 44 of an annular heating element 46.
Heating element 46 also includes annular side portions 48, 50 and a
bottom portion 56 which cooperate with the portion 44 to define an
annular duct 52 through which the liquid is communicated. The
bottom portion 56 is provided with an opening (not shown) which
permits fluid to communicate from the duct 52 into the annular
chamber 54. A pair of circumferentially spaced discs 55, 57 are
installed in the duct 52 and are held against the bottom portion 56
by leaf springs 59, 61. Discs 55, 57 are available commercially and
are made from a Positive Temperature Coefficient (PTC) electrically
resistive material.
The outlet fitting 18 communicates with a passage 58 within the
housing 12. A manually operable vent 60 is opened to vent the
passage 58 when the cartridge 14 is initially charged with liquid.
Operation of the primer pump 24 pressurizes the system to move
liquid from the inlet fitting 16 to the outlet fitting 18 while
purging the air which is displaced by the liquid through the vent
60, as will be more completely described hereinafter. The passage
58 terminates in a threaded stud 62 on which the removable
cartridge 14 may be engaged. The bottom portion 56 of element 46 is
fastened on the stud 60 by a nut 65.
The cartridge 14 comprises a casing 66 having a closed end 68 and
an opposite open end. The open end of the casing 66 is closed by a
reinforced bottom or tapping plate 70. The tapping plate 70
comprises a lightweight portion 72 which is crimped to the
periphery of the open end of the casing 66 in a manner common in
the art, and also includes a heavier portion 74 which is fastened
to the lighter portion 72. A circumferentially extending seal 76 is
retained in the groove on the lighter portion 72 and provides a
sealing connection between the casing 66 and the housing 12 when
the cartridge 14 is installed thereon. The heavier plate 74
includes an axially extending portion 77 which is threaded to
engage the stud 62 when the cartridge 14 is installed on the
housing 12. The tapping plate 70 is provided with a number of
circumferentially spaced openings 78 which communicate fluid from
the annular chamber 54 into the casing 66.
Mounted in the casing 66 is a coalescing medium generally indicated
by the numeral 82 which comprises a conventional circumferentially
extending array of radially tapering pleats of paper 84. Coalescing
medium 82 also includes an outer support member or screen 86, an
inner support member or screen 88, an upper end cap 90, and a lower
end cap 92. The lower end cap 92 is sealed to the walls of the
casing 66 by a circumferentially extending seal 94, to thereby
prevent fluid communication between a chamber 96 defined by the
medium 82 and the wall of the casing 66 and a sump 98 defined by
the end cap 92, the seal 94 and the bottom wall 68 of the casing
66. The coalescing medium 82 also includes a circumferentially
extending batt of a conventional fibrous filtering medium 100. The
fibrous filtering medium 100 circumscribes the outer screen 86 and
is comprised of randomly arrayed non-woven fibers having a density
much less than the density of the pleated paper medium 84.
Mounted coaxially within the coalescing medium 82 is a
conically-shaped separating medium generally indicated by the
numeral 102. The separating medium 102 comprises circumferentially
spaced supports 104 upon which a conventional separating membrane
106 is mounted. The separating medium 102 tapers towards the sump
98, so that water droplets coalesced by the coalescing medium 82
and separated out by the membrane 106 are permitted to fall down
into the sump 98 due to the conical shape of the separating medium
102. The separating medium 102 is coaxial with the stud 62 so that
liquid flowing through the membrane 106 may also flow upwardly
through the stud 62 into the passage 58. A relief valve generally
indicated by the numeral 108 is mounted in the tip 110 of the
medium 102, and opens to permit liquid flow through the passage 112
in the tip of the separating medium 102 when the pressure
differential across the membrane 106 exceeds a predetermined
level.
A circumferentially extending seal 114 circumscribes the stud 62
and includes a portion 116 which projects into the larger diameter
end of the conical separating medium 102, to provide a sealing
connection with the stud 62. The seal 114 also engages with the
threaded portion 77 of the plate 74, and still another portion 118
is clamped between the upper circumferential surface of the conical
separating medium 102, and the end cap 90 by a spring member 121. A
circumferentially extending baffle 122 projects downwardly from the
upper end cap 90 and is coaxial both with the inner screen 88 and
with the separating medium 102. The baffle 122 is impervious to
liquid flow.
Two electrical connections are necessary with respect to the
separating device 10. The discs 55, 57 are supplied with electrical
energy through a terminal 124 (FIG. 4) which projects from the top
of the housing 12 and is connected to a portion 126 extending from
the upper part 44 of the heating element 46. The casing 66 is also
provided with a combination drain for the sump 98 and warning probe
assembly generally indicated by the numeral 128. A pair of
conductors 130, 132 connects the probe assembly and water drain 128
with electrical ground and with a warning light on the vehicle
dashboard respectively to thereby indicate, as will be more
completely described hereinafter, that the sump 98 contains water
and should be drained.
The probe assembly 128 includes an annular fitting 136 secured to
the bottom of the sump 98 and defining a stepped bore 138
therewithin having a smaller diameter portion 140 and a larger
diameter portion 142. An electrically conductive probe 144 is
carried in an insulative housing 146. The housing 146 is threaded
as at 148 to threadedly engage a corresponding threaded portion on
the fitting 136. The threaded portion 148 is interrupted by
circumferentially spaced drain slots 150, 152 which are most
clearly shown on FIG. 6, and which extend axially through the
threaded portion 148 to permit fluid to drain as will be
hereinafter described.
The insulative housing 146 further carries axially spaced,
circumferentially extending O ring seals 154, 156. The O ring seal
154 engages the smaller diameter portion 140 of the fitting 136 and
the large diameter seal 156 engages the larger diameter portion 142
of the fitting 136. The seals 154, 156 and the corresponding
portions of the housing 146 and the fitting 136 cooperate to define
an annular cavity 158. A radially extending passage 160
communicates the cavity 158 with an axially extending passage 162
which extends through the lower portion (viewing FIG. 5) of the
housing 146. One end 164 of the probe 144 projects from the
corresponding end of the housing 146 to be exposed to the liquid
content in the sump 98, and the other end of the probe 144
terminates in a transversely projecting portion 166. The prove 144
also includes an intermediate portion 168 which bends around, and
is circumferentially spaced from, the radial passage 160 and
longitudinal passage 162.
A terminal assembly generally indicated by the numeral 170 connects
the conductors 130, 132 with the probe assembly. The terminal
assembly includes a circumferentially extending portion 172 which
circumscribes the fitting 136 and housing 146. A pair of axially
spaced rings 174, 176 are carried in the circumferentially
extending ring-like portion 172 of terminal assembly 170, and
circumscribe the housing 146. The ring 174 is exposed for
electrical engagement with the fitting 136, and a block of
electrically insulative material 178 isolates the ring 174 from the
ring 176. The ring 176 is connected to the conductor 132, and is
exposed for electrical contact with the transversely projecting
portion 166 of the probe 144. As can most clearly be seen in FIG.
5, the ring 176 will be in electrical contact with the transversely
projecting portion 166 regardless of the angular orientation of the
projecting portion 166.
In operation, the inlet and outlet fittings 16, 18 of the
separating device 10 are installed in an appropriate liquid flow
system, such as the fuel supply system to a motor vehicle diesel
engine. Liquid communicated through the inlet fitting 16 passes
through the inlet passage 20 and then flows through check valves 36
and 38 into passage portion 40. Liquid then flows from passage
portion 40 into the duct 52. When the temperature of the liquid is
sufficiently low, the heating discs 55, 57 heat the fuel oil to a
temperature high enough to avoid the "waxing" problem, as will be
hereinafter described. The liquid mixture then flows from the
heating element 46 into the annular chamber 54 through the
aforementioned openings (not shown) in support plate 56. Liquid in
the annular chamber 54 is communicated through the openings 78 into
the cartridge 14. Liquid in the cartridge is deflected by the end
cap 90 into the annular chamber 96. The liquid mixture then passes
into the coalescing medium 82. Flow of liquid through the
coalescing medium 82 causes the liquid to be separated out of the
mixture, such as water from a mixture of fuel oil and water, to
agglomerate into water droplets. As these water droplets appear on
the inner screen 88 of the coalescing medium 82, gravity causes
most of the particles to fall into the sump 98. The liquid mixture,
now relieved of at least some of the water or other liquid
component to be removed, now flows around the end of the impervious
baffle 122. The baffle 122 assures that the liquid flow reverses
direction before entering the separating medium 102. This reversal
of direction, from the generally downwardly movement viewing FIG. 1
of the liquid mixture from the openings 78 through the chamber 96
and the coalescing medium 82 to the generally upwardly flow of the
liquid mixture into the separating cartridge 102, further
encourages any droplets of the heavier component (such as water)
that is to be removed from the mixture to fall into the sump. The
membrane 106 of the separating medium 102 is repellent to, for
example, water, so that any of the water droplets remaining in the
liquid mixture will collect on the surface of the membrane, and,
because of the conical shape of the membrane, will tend to drain
downwardly viewing FIG. 1 into the sump 98. The liquid, now
relieved of the liquid component removed by the separator, then
flows through the threaded stud 62 into the passage 58 and out of
the outlet fitting 18.
The liquid component removed from the liquid mixture by the
separating device 10 will gradually fill the sump 98. The sump 98
is initially filled with the liquid mixture which, in the case of a
mixture of fuel oil and water in which the water contaminant makes
up only a very small percentage of the total mixture, the
conductivity of the mixture is such that a high impedance circuit
will exist between the projecting portion 164 of the probe and the
grounded fitting 136, so that a high impedance circuit between the
conductors 130, 132 is present. Accordingly, the aforementioned
dashboard light (not shown) will be turned off. However, as water
is removed from the liquid mixture and fills the sump 98, the
impedence of the electrical circuit between the probe 144 and the
fitting 136 will be abruptly reduced when the level of the water
reaches the projecting portion 164. When this occurs, the dashboard
light is turned on through a conventional control circuit (not
shown) which responds to the change of impedence. Accordingly, the
vehicle operator is warned that the sump 98 must be drained.
Draining the sump 98 is accomplished by manipulating the portion
180 of the probe assembly to unscrew the housing 146 from the
fitting 136 until the O ring seal 154 is moved out of the smaller
diameter portion 140 of the bore 138 and into the larger diameter
portion 142 of the latter. When this occurs, water in the sump 98
drains into the circumferentially extending cavity 158. The O ring
seal 156 protects the connection between the probe transversely
extending portion 166 from water contamination. Water in the cavity
158 drains through radially extending passages 160 and axially
extending passage 162 to the exterior of the separator 10.
The sump 98 may be purged of water without introducing air into the
sytem by first opening the drain as described hereinabove and by
then manipulating the plunger 32 of the primer pump 24, to thereby
force the liquid mixture from the inlet fitting 16 into the
cartridge 14 to thereby displace the water through the open drain.
The primer pump 24 operates in the normal manner, in which upward
movement of the plunger 32 due to the spring 34 creates a partial
vacuum in the pumping chamber 22, thereby drawing liquid into the
pumping chamber 22 through the inlet fitting 16 and the check valve
36. Since no air is introduced into the system, vent 60 remains
closed. When the plunger is pushed downwardly viewing FIG. 1, the
fluid content of the pumping chamber 22 is expelled into the
passage portion 40 through the check valve 38.
From time to time the medium within the cartridge 14 lose their
effectiveness and must be replaced. Accordingly, the cartridge 14
must then be removed from the housing 12 and replaced with a new
cartridge. Removal of the cartridge is accomplished by unscrewing
the housing 146 from the fitting 136 so that the probe assembly 128
is entirely removed from the fitting 136. The terminal assembly 170
is held onto the fitting 136 by the probe assembly and is removed
with it. The entire cartridge 14 is then removed from the threaded
stud 62 in the conventional manner. A new cartridge 14 is then
installed on the stud 62 and tightened until the circumferentially
extending seal 76 sealingly engages the housing 12. The portion 116
of the seal 114 is forced over the end of the stud 62 when the
cartridge 14 is installed thereon and automatically engages the
outer circumferential surface of the stud 62 to form a sealing
connection therewith. The probe housing 146 and terminal assembly
170 are then installed on the fitting 136 on the new cartridge.
When the cartridge is installed on the housing, the air in the new
cartridge must be purged so that when the separating device is used
in the fuel supply system of a diesel engine, the air in the
cartridge will not be communicated to the engine to cause problems.
Accordingly, the primer pump 24 is operated to pump fluid from the
inlet fitting 16 into the new cartridge 14. As the cartridge 14
fills with the liquid mixture, the mixture eventually will begin
coming out of the vent 60. At that time, the vent 60 is closed.
As discussed hereinabove, diesel fuel exhibits a phenomena known as
"waxing" when it is cooled to a predetermined level. When waxing
occurs, wax crystals form due to the paraffin in diesel fuels.
These wax crystals in the diesel fuel cause problems when they are
communicated through any filter or separator in the fuel line,
because the wax crystals tend to act as a contaminant that plugs
the filter or separating media thereby causing a fuel blockage or
diminished flow through the filter or separating device. Although
prior art fuel oil heaters have been used, they are relatively
ineffective in preventing wax crystals from clogging the filter,
because the heaters are only effective for the fuel in the area
where the heater is installed. If the fuel filter/separator is
blocked due to waxing, the heater is not effective because there is
no way to communicate heated fuel oil through the filter/separator.
Referring to FIG. 1, the batt of loosely packed fibrous filtering
medium 100 which circumscribes the coalescing medium 84 tends to
collect wax crystals on the fibers. Since the medium 100 is much
less dense than is the medium 84, the wax crystals tending to
collect on the fibers do not span the open pores of the batt-like
material 100, thus protecting the tighter and more dense coalescing
medium 84 from plugging during initial flow through the filter.
When the pressure differential across the separator medium 102
becomes sufficiently great, such as would occur during wax crystals
plugging the separating membrane, the relief valve 110 opens to
permit fuel flow to bypass the waxed separator membrane 106.
Accordingly, fuel flow through the cartridge is permitted, thereby
permitting the heater 46 to heat the fuel flow and to permit the
heated fuel flow to pass to the cartridge 14. Of course, the relief
valve closes when the pressure level drops to an acceptable level
due to the operation of the heater dissolving the wax crystals in
the fuel.
* * * * *